/****************************************************************************
 *
 * Copyright 2018 Samsung Electronics All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
 * either express or implied. See the License for the specific
 * language governing permissions and limitations under the License.
 *
 ****************************************************************************/
/****************************************************************************
 * arch/arm/src/stm32/stm32_procfs_ccm.c
 *
 *   Copyright (C) 2014 Pelle Windestam. All rights reserved.
 *   Author: Pelle Windestam (pelle@windestam.se)
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 * 3. Neither the name NuttX nor the names of its contributors may be
 *    used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 ****************************************************************************/

/****************************************************************************
 * Included Files
 ****************************************************************************/

#include <tinyara/config.h>

#include <sys/types.h>
#include <sys/statfs.h>
#include <sys/stat.h>

#include <stdint.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <assert.h>
#include <errno.h>
#include <debug.h>

#include <tinyara/arch.h>
#include <tinyara/sched.h>
#include <tinyara/kmalloc.h>
#include <tinyara/fs/fs.h>
#include <tinyara/fs/procfs.h>
#include <tinyara/fs/dirent.h>

#include <arch/irq.h>

#include "stm32_ccm.h"

#if !defined(CONFIG_DISABLE_MOUNTPOINT) && defined(CONFIG_FS_PROCFS)

/****************************************************************************
 * Pre-processor Definitions
 ****************************************************************************/
#define CCM_LINELEN     64

/****************************************************************************
 * Private Types
 ****************************************************************************/
/* This enumeration identifies all of the thread attributes that can be
 * accessed via the procfs file system.
 */

/* This structure describes one open "file" */

struct ccm_file_s {
	struct procfs_file_s base;	/* Base open file structure */
	unsigned int linesize;		/* Number of valid characters in line[] */
	char line[CCM_LINELEN];		/* Pre-allocated buffer for formatted lines */
};

/****************************************************************************
 * Private Function Prototypes
 ****************************************************************************/
/* File system methods */

static int ccm_open(FAR struct file *filep, FAR const char *relpath, int oflags, mode_t mode);
static int ccm_close(FAR struct file *filep);
static ssize_t ccm_read(FAR struct file *filep, FAR char *buffer, size_t buflen);
static int ccm_dup(FAR const struct file *oldp, FAR struct file *newp);
static int ccm_stat(FAR const char *relpath, FAR struct stat *buf);

/****************************************************************************
 * Private Variables
 ****************************************************************************/

/****************************************************************************
 * Public Variables
 ****************************************************************************/

/* See include/nutts/fs/procfs.h
 * We use the old-fashioned kind of initializers so that this will compile
 * with any compiler.
 */

const struct procfs_operations ccm_procfsoperations = {
	ccm_open,					/* open */
	ccm_close,					/* close */
	ccm_read,					/* read */
	NULL,						/* write */
	ccm_dup,					/* dup */
	NULL,						/* opendir */
	NULL,						/* closedir */
	NULL,						/* readdir */
	NULL,						/* rewinddir */
	ccm_stat					/* stat */
};

/****************************************************************************
 * Private Functions
 ****************************************************************************/

/****************************************************************************
 * Name: ccm_open
 ****************************************************************************/

static int ccm_open(FAR struct file *filep, FAR const char *relpath, int oflags, mode_t mode)
{
	FAR struct ccm_file_s *priv;

	fvdbg("Open '%s'\n", relpath);

	/* PROCFS is read-only.  Any attempt to open with any kind of write
	 * access is not permitted.
	 *
	 * REVISIT:  Write-able proc files could be quite useful.
	 */

	if ((oflags & O_WRONLY) != 0 || (oflags & O_RDONLY) == 0) {
		fdbg("ERROR: Only O_RDONLY supported\n");
		return -EACCES;
	}

	/* "cpuload" is the only acceptable value for the relpath */

	if (strcmp(relpath, "ccm") != 0) {
		fdbg("ERROR: relpath is '%s'\n", relpath);
		return -ENOENT;
	}

	/* Allocate a container to hold the task and attribute selection */

	priv = (FAR struct ccm_file_s *)kmm_zalloc(sizeof(struct ccm_file_s));
	if (!priv) {
		fdbg("ERROR: Failed to allocate file attributes\n");
		return -ENOMEM;
	}

	/* Save the index as the open-specific state in filep->f_priv */

	filep->f_priv = (FAR void *)priv;
	return OK;
}

/****************************************************************************
 * Name: ccm_close
 ****************************************************************************/

static int ccm_close(FAR struct file *filep)
{
	FAR struct ccm_file_s *priv;

	/* Recover our private data from the struct file instance */

	priv = (FAR struct ccm_file_s *)filep->f_priv;
	DEBUGASSERT(priv);

	/* Release the file attributes structure */

	kmm_free(priv);
	filep->f_priv = NULL;
	return OK;
}

/****************************************************************************
 * Name: ccm_read
 ****************************************************************************/

static ssize_t ccm_read(FAR struct file *filep, FAR char *buffer, size_t buflen)
{
	FAR struct ccm_file_s *priv;
	size_t linesize;
	size_t copysize;
	size_t remaining;
	size_t totalsize;
	struct mallinfo mem;
	off_t offset = filep->f_pos;

	fvdbg("buffer=%p buflen=%d\n", buffer, (int)buflen);

	/* Recover our private data from the struct file instance */

	priv = (FAR struct ccm_file_s *)filep->f_priv;
	DEBUGASSERT(priv);

	mm_mallinfo(&g_ccm_heap, &mem);

	remaining = buflen;
	totalsize = 0;

	linesize = snprintf(priv->line, CCM_LINELEN, "             total       used       free    largest\n");
	copysize = procfs_memcpy(priv->line, linesize, buffer, remaining, &offset);
	totalsize += copysize;
	buffer += copysize;
	remaining -= copysize;

	if (totalsize >= buflen) {
		return totalsize;
	}

	linesize = snprintf(priv->line, CCM_LINELEN, "Mem:   %11d%11d%11d%11d\n", mem.arena, mem.uordblks, mem.fordblks, mem.mxordblk);
	copysize = procfs_memcpy(priv->line, linesize, buffer, remaining, &offset);
	totalsize += copysize;

	/* Update the file offset */

	if (totalsize > 0) {
		filep->f_pos += totalsize;
	}

	return totalsize;
}

/****************************************************************************
 * Name: ccm_dup
 *
 * Description:
 *   Duplicate open file data in the new file structure.
 *
 ****************************************************************************/

static int ccm_dup(FAR const struct file *oldp, FAR struct file *newp)
{
	FAR struct ccm_file_s *oldpriv;
	FAR struct ccm_file_s *newpriv;

	fvdbg("Dup %p->%p\n", oldp, newp);

	/* Recover our private data from the old struct file instance */

	oldpriv = (FAR struct ccm_file_s *)oldp->f_priv;
	DEBUGASSERT(oldpriv);

	/* Allocate a new container to hold the task and attribute selection */

	newpriv = (FAR struct ccm_file_s *)kmm_zalloc(sizeof(struct ccm_file_s));
	if (!newpriv) {
		fdbg("ERROR: Failed to allocate file attributes\n");
		return -ENOMEM;
	}

	/* The copy the file attributes from the old attributes to the new */

	memcpy(newpriv, oldpriv, sizeof(struct ccm_file_s));

	/* Save the new attributes in the new file structure */

	newp->f_priv = (FAR void *)newpriv;
	return OK;
}

static int ccm_stat(const char *relpath, struct stat *buf)
{
	if (strcmp(relpath, "ccm") != 0) {
		fdbg("ERROR: relpath is '%s'\n", relpath);
		return -ENOENT;
	}

	buf->st_mode = S_IFREG | S_IROTH | S_IRGRP | S_IRUSR;
	buf->st_size = 0;
	buf->st_blksize = 0;
	buf->st_blocks = 0;

	return OK;
}

#endif							/* !CONFIG_DISABLE_MOUNTPOINT && CONFIG_FS_PROCFS */
